@_cadrej I think one of the key things is high standards and low autonomy until proven otherwise (for example, there're like only 5 students I trust with unmonitored Chromebook time after their work is done, and they've earned it by being on top of things and respectful all semester).
@_cadrej Honestly treating them (high schoolers) like small children. It's very helpful. Everything is routine based. Everything is a discussion of respectful and kind classroom behavior. Call/contact parents as much as possible. Do activities, small quizzes, games, rewards.
@_cadrej Consequences mirror younger grades too. First time is a check-in/redirect. Second time is a warning. Third time is a consequence (moving seat, hallway talk, call home, losing free time, staying 2 min after class, etc.). Fourth time is classroom removal and document incident.